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University of Nevada, Las Vegas

Public Policy and Leadership Faculty Publications

Plant Sciences

Articles 1 - 17 of 17

Full-Text Articles in Physical Sciences and Mathematics

Disturbance And Plant Succession In The Mojave And Sonoran Deserts Of The American Southwest, Scott R. Abella Mar 2010

Disturbance And Plant Succession In The Mojave And Sonoran Deserts Of The American Southwest, Scott R. Abella

Public Policy and Leadership Faculty Publications

Disturbances such as fire, land clearing, and road building remove vegetation and can have major influences on public health through effects on air quality, aesthetics, recreational opportunities, natural resource availability, and economics. Plant recovery and succession following disturbance are poorly understood in arid lands relative to more temperate regions. This study quantitatively reviewed vegetation reestablishment following a variety of disturbances in the Mojave and Sonoran Deserts of southwestern North America. A total of 47 studies met inclusion criteria for the review. The time estimated by 29 individual studies for full reestablishment of total perennial plant cover was 76 years. Although …

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Relating Surface Backscatter Response From Trmm Precipitation Radar To Soil Moisture: Results Over A Semi-Arid Region, Haroon Stephen, Sajjad Ahmad, Thomas C. Piechota, Chunling Tang Jan 2010

Relating Surface Backscatter Response From Trmm Precipitation Radar To Soil Moisture: Results Over A Semi-Arid Region, Haroon Stephen, Sajjad Ahmad, Thomas C. Piechota, Chunling Tang

Public Policy and Leadership Faculty Publications

The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σº) of the surface. σº is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σº primarily depends on the soil water content. In this study we relate TRMMPR σº measurements to soil water content (m(s)) in the Lower Colorado River Basin (LCRB). σº dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σº that couples incidence angle, m(s), and NDVI is used …

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Trying To Beat The Brome: Understanding Establishment Thresholds And Choosing Competitive Native Species At Parashant National Monument, Scott R. Abella, E. Cayenne Engel Jan 2010

Trying To Beat The Brome: Understanding Establishment Thresholds And Choosing Competitive Native Species At Parashant National Monument, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Desert fires fueled by exotic grasses like the omnipresent red brome (Bromus rubens) can be intense and cause widespread mortality of native vegetation. Native desert scrub communities such as those dominated by blackbrush (Coleogyne ramosissima) do not readily reestablish after fire (Abella 2009) and may even become more abundant in the post-burn landscape initiating a fire cycle that occurs at a greater frequency than the recovery time of the long-lived desert perennial community.

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Native Species Interactions With Red Brome: Suggestions For Burn-Area Revegetation, Scott R. Abella Jan 2010

Native Species Interactions With Red Brome: Suggestions For Burn-Area Revegetation, Scott R. Abella

Public Policy and Leadership Faculty Publications

In deserts, native perennial plants often actually facilitate the establishment of exotic annual grasses. One of our focal areas of research is to identify native species for use in revegetation projects that reduce the establishment of exotic annual grasses, or at least do not strongly facilitate exotic species establishment. An initial research effort involving a competition experiment of red brome with native species and a correlational field study of brome distribution among native perennial plants is in press with the journal Invasive Plant Science and Management.

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Heat And Smoke Effects On Red Brome Soil Seed Banks, Scott R. Abella, E. Cayenne Engel Oct 2009

Heat And Smoke Effects On Red Brome Soil Seed Banks, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Management of exotic plants that are annuals entails understanding and managing their soil seed banks. We completed a study of the influences of heat and liquid smoke on red brome (Bromus rubens) soil seed banks collected from Red Rock Canyon in southern Nevada as part of a collaborative fire effects monitoring effort with Bureau of Land Management - Las Vegas. We collected the samples from the 2005 Loop Fire, where we observed in a monitoring field study that exotic grasses such as red brome were relatively sparse in the first 2-3 years (which were during a dry period) following the …

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Early Post-Fire Plant Establishment On A Mojave Desert Burn, Scott R. Abella, E. Cayenne Engel, Christina L. Lund, Jessica E. Spencer Jan 2009

Early Post-Fire Plant Establishment On A Mojave Desert Burn, Scott R. Abella, E. Cayenne Engel, Christina L. Lund, Jessica E. Spencer

Public Policy and Leadership Faculty Publications

Fire has become more extensive in recent decades in southwestern United States arid lands. Burned areas pose management challenges and opportunities, and increasing our understanding of post-fire plant colonization may assist management decision-making. We examined plant communities, soils, and soil seed banks two years after the 2005 Loop Fire, located in a creosote-blackbrush community in Red Rock Canyon National Conservation Area in southern Nevada’s Mojave Desert. Based on a spring sampling of 20, 0.01-ha plots, live + dead cover of the exotic annual Bromus rubens averaged nine times lower on the burn than on a paired unburned area. Perennial species …

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Progress In Strategic Research Areas, Scott R. Abella Jan 2009

Progress In Strategic Research Areas, Scott R. Abella

Public Policy and Leadership Faculty Publications

Three years ago through conversations with resource managers, assessing the status of knowledge of the scientific literature, and our own interests, we set forth several strategic research areas that we believed would be timely for advancing Mojave Desert conservation and management.

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Estimating Soil Seed Bank Characteristics In Ponderosa Pine Forests Using Vegetation And Forest-Floor Data, Scott R. Abella, Judith D. Springer Sep 2008

Estimating Soil Seed Bank Characteristics In Ponderosa Pine Forests Using Vegetation And Forest-Floor Data, Scott R. Abella, Judith D. Springer

Public Policy and Leadership Faculty Publications

Soil seed banks are important for vegetation management because they contain propagules of species that may be considered desirable or undesirable for site colonization after management and disturbance events. Knowledge of seed bank size and composition before planning management activities facilitates proactive management by providing early alerts of exotic species presence and of abilities of seed banks to promote colonization by desirable species. We developed models in ponderosa pine (Pinus ponderosa) forests in northern Arizona to estimate the size and richness of mineral soil seed banks using readily observable vegetation and forestfloor characteristics. Regression models using three or fewer predictors …

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Plant Community Response To Fire: A Chronosequence Study, Scott R. Abella, E. Cayenne Engel Apr 2008

Plant Community Response To Fire: A Chronosequence Study, Scott R. Abella, E. Cayenne Engel

Public Policy and Leadership Faculty Publications

Fires are becoming more prevalent events across the landscape in the southwestern US. Over the next several decades the already arid southwest is predicted to become warmer and drier, with longer summers, and an increase of “extreme” weather events such as lightening inducing thunderstorms. While the “hotter and drier” forecast may indicate less abundant plant life, and thus less available biomass for fuel, exotic invasive plant species are becoming more dominant across the landscape with increases in human travel and commerce. Exotic species (particularly many of the invasive grasses) are adding fuel for the fires to burn when the annuals …

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Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace Jan 2007

Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace

Public Policy and Leadership Faculty Publications

Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive …

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Forest-Floor Treatments In Arizona Ponderosa Pine Restoration Ecosystems: No Short-Term Effects On Plant Communities, Scott R. Abella, W. Wallace Covington Jan 2007

Forest-Floor Treatments In Arizona Ponderosa Pine Restoration Ecosystems: No Short-Term Effects On Plant Communities, Scott R. Abella, W. Wallace Covington

Public Policy and Leadership Faculty Publications

Leaf litter accumulation during fire exclusion and increases in tree density in postsettlement southwestern Pinus ponderosa forests may limit the establishment of understory vegetation. We performed an experiment in P. ponderosa forests of northern Arizona to ascertain plant community responses to forest-floor scarification and Oi removal on thirty-six 100-m2 plots overlaid on an existing ecological restoration experiment that involved tree thinning and prescribed burning. Constrasting with findings from many other forest types, forest-floor treatments had no effect on community diversity or composition during the 2-year experiment. Sørensen similarities were as high as 97% between posttreatment years within treatments; and successional …

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Canopy-Tree Influences Along A Soil Parent Material Gradient In Pinus-Ponderosa-Quercus Gambelii Forests, Northern Arizona, Scott R. Abella, Judith D. Springer Jan 2006

Canopy-Tree Influences Along A Soil Parent Material Gradient In Pinus-Ponderosa-Quercus Gambelii Forests, Northern Arizona, Scott R. Abella, Judith D. Springer

Public Policy and Leadership Faculty Publications

ABELLA, S. R. (Public Lands Institute and School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-2040) AND J. D. SPRINGER (Ecological Restoration Institute, Northern Arizona University, Flagstaff, AZ 86011-5017). Canopy-tree influences along a soil parent material gradient in Pinus ponderosa- Quercus gambelii forests, northern Arizona. J. Torrey Bot. Soc. 135: 26–36. 2008.—The distribution of canopy trees can impose within-site patterns of soil properties and understory plant composition. At ten sites spanning a soil parent material gradient in northern Arizona Pinus ponderosa-Quercus gambelii forests, we compared soils and plant composition among five canopy types: openings, Pinus ponderosa …

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Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer Jan 2004

Fifteen Years Of Plant Community Dynamics During A Northwest Ohio Oak Savanna Restoration, Scott R. Abella, John F. Jaeger, Lawrence G. Brewer

Public Policy and Leadership Faculty Publications

Midwest oak savanna communities are noted for their unusual plant assemblages, but these communities have been reduced by more than 98% because of changing land uses and conversion to closed-canopy forests. We initiated an ongoing 15-year experiment in 1988 to restore a 40-ha black oak (Quercus velutina) savanna by applying burn treatments that historically maintained this vegetation type. Groundlayer composition changed significantly for both the burn treatment and the control, with the burn treatment exhibiting slight increases in herbs such as wild lupine (Lupinus perennis) and hairy puccoon (Lithospermum caroliniense), both of which are species requiring greater insolation. Burn treatments …

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Tree Thinning And Prescribed Burning Effects On Ground Flora In Arizona Ponderosa Pine Forests: A Review, Scott R. Abella Jan 2004

Tree Thinning And Prescribed Burning Effects On Ground Flora In Arizona Ponderosa Pine Forests: A Review, Scott R. Abella

Public Policy and Leadership Faculty Publications

Ground flora is an important response variable to monitor after tree thinning and prescribed burning treatments designed to restore Arizona ponderosa pine (Pinus ponderosa P.& C. Lawson) forests. This paper reviews published literature on the effects of thinning and burning on ground flora in Arizona ponderosa pine forests in five main categories of research: ground flora biomass, species diversity, plant community composition, population processes, and individual species ecology. Research published to date suggests that thinning and burning generally increase ground flora biomass, whereas other categories of research such as community composition and population processes have been little studied in Arizona …

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Ecology Of Eastern Prickly Pear Cactus (Opuntia Humifusa) In Oak Openings Preserve, Northwestern Ohio, Scott R. Abella, John F. Jaeger Jan 2004

Ecology Of Eastern Prickly Pear Cactus (Opuntia Humifusa) In Oak Openings Preserve, Northwestern Ohio, Scott R. Abella, John F. Jaeger

Public Policy and Leadership Faculty Publications

Opuntia humifusa (eastern prickly pear cactus) is listed as potentially threatened in Ohio, and we examined the characteristics of O. humifusa sites in Oak Openings Preserve in northwestern Ohio’s Oak Openings region in an attempt to provide data that may help protect this species. Opuntia humifusa occurrences were associated with loose sands of the xeric Udipsamment Ottokee and Oakville soil series on sites that had been cleared before the 1940s during failed agricultural attempts. Shading by encroaching canopy trees is a threat to several O. humifusa populations in Oak Openings Preserve, and treatments that reduce canopy cover at these sites …

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Ecological Species Groups Of South Carolina's Jocassee Gorges, Southern Appalachian Mountains, Scott R. Abella, Victor B. Shelburne Jan 2004

Ecological Species Groups Of South Carolina's Jocassee Gorges, Southern Appalachian Mountains, Scott R. Abella, Victor B. Shelburne

Public Policy and Leadership Faculty Publications

Ecological species groups, consisting of assemblages of co-occurring plant species exhibiting similar environmental affinities, were developed for ground-flora and tree strata in late- successional forests on a 13,000 ha southern Appalachian landscape. We distinguished 11 ground-flora groups that included 50 species and six tree groups comprised of 19 species. Ground-flora groups ranged from a xeric Vaccinium group (including Vaccinium pallidum, Euphorbia corollata, and Piptochaetium avenaceum) to a mesic Rhododendron group (typified by Rhododendron maximum, Mitchella repens, and Hexastylis heterophylla). Tree groups ranged from a Quercus coccinea group to a Tsuga canadensis group. Consistent with previous research, species groups exhibited a …

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Spatial And Temporal Patterns Of Eastern White Pine Regeneration In The Northwestern Ohio Oak Stand, Scott R. Abella, Neil W. Macdonald Jan 2002

Spatial And Temporal Patterns Of Eastern White Pine Regeneration In The Northwestern Ohio Oak Stand, Scott R. Abella, Neil W. Macdonald

Public Policy and Leadership Faculty Publications

Eastern white pine (Pinus strobus L.) was often associated with oaks (Quercus spp.) on upland sites in presettlement forests of the upper Great Lakes region, but widespread logging and subsequent fires in the late 1800s converted these upland sites to fire-tolerant oak forests. Although white pine regeneration is occurring in these second-growth oak forests, white pine regeneration patterns in oak forests of the Great Lakes region are not well documented. We examined white pine regeneration in the southern Great Lakes region in an oak stand within the Oak Openings region of northwestern Ohio, where white pine plantations established in the …

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